Analysis of carbapenemases genes of carbapenem-resistant Klebsiella pneumoniae isolated from Tehran heart center

Emerging of carbapenem-resistant Klebsiella pneumoniae (CRKP) is one of the major concerns among healthcare systems. This study aimed to investigate the antibiotic susceptibility pattern and carbapenemase genes of carbapenemase-producing K. pneumoniae isolates obtained from Iranian hospitalized patients.

This study was performed on 71 CRKP strains isolated from different clinical specimens collected in Tehran Heart Center (Tehran, Iran). A Modified Hodge test (MHT) was done for the detection of carbapenemase-producing K. pneumoniae. The presence of blaKPC, blaVIM, blaIMP, blaNDM, and blaOXA-48-type carbapenemases was evaluated by the PCR method.

We identified 8.82% (71/805) of K. pneumoniae isolates as CRKP by MHT test. The antibiotic susceptibility indicated that all isolates were resistant to imipenem, meropenem, cefotaxime, ceftazidime, cefepime, ceftriaxone, cephalothin, ciprofloxacin, and augmentin, and then mostly resistant to aztreonam, cefoxitin, gentamicin, and trimethoprim/sulfamethoxazole with 98.6%, 98.6%, 97.2%, and 94.4%, respectively. The lowest resistance was related to amikacin with 46.5% (33/71 isolates). The level of imipenem MIC for all carbapenem-resistant isolates was estimated ≥32 µg/mL. Among positive isolates for carbapenemase genes, the most frequent gene was blaOXA-48. It was found in 48 (67.6%) isolates followed by blaVIM in 28 (39.4%) isolates. blaIMP, blaNDM, and blaKPC genes were identified in 19 (26.8%), 13 (18.3%) and 5 (7.0%) isolates, respectively. These genes were not detected in nine isolates.

The relatively high frequency of some carbapenemase genes suggests major concern about the emergence of isolates containing carbapenem resistance genes as a potential health threat.